It is well known that outside light such as sunlight is taken into the interior of a building through a so-called window glass or the like such that a comfortable indoor space is formed. By contrast, several technologies have so far been proposed in which direct sunlight is controlled such that outside light is taken in a more comfortable form.
For example, patent document 1 discloses a light control sheet that is arranged in a light taking-in portion which takes sunlight into a building and that is used for controlling the taking in of sunlight. In the light control sheet, the entire sheet is formed with a light transmission portion made of a light transmission material which transmits sunlight and a light shield portion group made of a light absorption material which absorbs sunlight, and in the light shield portion group, in one direction within the sheet, with a predetermined pitch, a plurality of a light shield portions made of the light absorption material are aligned.
According to technologies disclosed in patent documents 2 to 4, an interface that has a predetermined geometric configuration such as a prism and has a refractive index difference is utilized, and thus control is performed by deflecting and reflecting outside light such as sunlight in a desired direction.